1. Field of the Invention
The present invention generally relates to a device for diagnosing and removing obstructions within the lumens of hollow, substantially tubular structures and more particularly to such a device adapted for use in diagnosing and removing obstructions in blood vessels.
2. Description of the Prior Art
The debilitating effects of obstructions to the flow of blood in the cardiovascular system of humans and animals have long been recognized. Such obstructions can take many forms and arise in many different manners. For instance, accretion of inorganic and organic materials on the walls of blood vessels have long been known as a cause of an overall reduction in the cross-sectional area of the lumen of the vessel with a consequent diminishing effect on the rate of blood flow therethrough. Further, a number of pathologies have been identified as the cause of intravascular occlusions and partial obstructions, such as atheromas and the like.
While some such obstructions respond favorably to medicinal or chemical treatment, either to effect a dilation of the vessel or a chemically induced erosion or to induce the breaking up or dissolution of the material obstructing the blood vessel, it has long been known that such chemical applications have limited utility and are restricted to use in a rather insubstantial portion of pathological environments, particularly those involving tissue growth across the lumen or bore of a blood vessel.
Various apparatuses have been proposed which are adapted for use in physically intervening within the vascular cavity to remove the obstruction. For example, it has been proposed to employ laser generating or similar apparatuses to cause a disintegration of the obstruction of the blood vessel. While some such apparatuses are useful for their intended purposes, it has long been known that associated devices and methods for permitting the visualization of the pathological tissue during and prior to the attempted removal thereof have been largely deficient and unsatisfactory in one or more respects, such as the inability accurately to gauge the dimensions of the obstruction before and during the performance of the removal technique for which the therapeutic apparatus is intended to be used. The use of the various visualization methods and devices heretofore proposed often necessitates the interruption of blood flow through the vessel being treated, or require interruption of the treatment period for substantial periods of time, in order that the remaining portions of the obstruction can be visualized. Thus, it has been known that conventional visualization techniques and devices used in conjunction with known therapeutic tools and apparatuses for the removal of obstructions often do not permit accurate determinations of obstruction dimensions during treatment for precise imaging of the progressive reduction of the obstruction during the treatment, whereby the treatment can be minimized substantially to that necessary without exceeding safe levels of treatment.
Therefore, it has long been known that it would be desirable to have an improved device for visualizing obstructions in the lumens of cardiovascular vessels and the like and for removing such obstructions. Further, it has long been known that it would be desirable to have such a device which can be constructed in a variety of dimensions for use in removing pathological growths, inorganic accumulations, and other obstructions to free blood flow in blood vessels of varying sizes with a precision of imagery and therapeutic application heretofore unattainable.